Sylvester Stallone was accused of sexually assaulting a 16-year-old girl at a Las Vegas hotel in 1986, according to a report.

The unnamed teen told Vegas cops that in July 1986, the “Rocky” star “intimidated” her into having sex with him and his bodyguard, Michael De Luca, at the former Las Vegas Hilton hotel, where Stallone was staying while shooting a movie in Sin City, according to a police report obtained by the Daily Mail.

While having sex with the teen, Stallone, then 40, encouraged De Luca to join them, which made her feel “very uncomfortable,” the girl told police. She felt she had “no choice” but to participate, she said, according to the Daily Mail.

De Luca, who was killed in 2013, made her give him oral sex, then “came around and had vaginal sex with her,” the report says. Stallone then allegedly “made her give him a blow job.”

The girl, who was staying at the hotel with family friends, said Stallone threatened to “beat her head in” if she told anyone about the threesome, then laughed about it with De Luca, the report says.

The young woman only talked to police when cops tracked her down after learning about the incident from a hotel employee. She told cops she didn’t pursue charges because she was “humiliated” and “scared,” according to the report.

“She indicated that if the sexual encounter had only been with Stallone, she would not pursue this matter, but due to the fact that Mike, the bodyguard became involved in the sexual incident, she didn’t know what she wanted to do,” the report says.

The teen ended up signing a no-prosecution form and the issue was dropped, according to the Daily Mail.

Stallone was in Vegas to film “Over the Top” when the alleged assault took place. The 16-year-old said she met the “Rambo” star through actor David Mendenhall, who introduced her to Stallone in an elevator.

A couple days later, she got Stallone’s autograph, at which point the actor asked how old she was, the teen told police.

“She told him she was 16, going on 17 years of age,” the report reads. “She told me that Stallone asked her how she got such a build and she said that she just blushed.”

The next day, De Luca gave her two keys to a room on the 27th floor, where the alleged assault took place.